What is claim preclusion?

Claim preclusion is what keeps parties from suing each other again after a final judgment on the merits is reached in a civil litigation. For example, if a plaintiff prevails in a lawsuit against a defendant or loses a case against a defendant in Case A, the plaintiff probably cannot sue the defendant again based on the same events in Case B. Even if the plaintiff sues in a different court or alleges new causes of action, Case B is probably barred by claim preclusion.

For example, let’s say after a car accident Patty sues David for negligence in Case A. The jury in Case A rules against Patty. Patty probably can’t sue David again based on the car accident. Even if she sues in a different court or alleges battery instead of negligence, the case is probably barred.

Three things to look for in a case where claim preclusion might apply:

1. Were the same parties involved in a prior litigation?

2. Is the second lawsuit based on the same events as the first lawsuit?

3. Were the causes of action (e.g., negligence) in the second case already litigated in the first case? Could the causes of action in the second case have been raised in the first case?

If the answers to these questions are “Yes” then claim preclusion probably applies.